Dear Muhammad,

I'm attaching an interesting paper about the effect of hydrogen passivation on the electronic structure, which provide the basic concept for distinguishing the change in the DOS and the band structure in the case of 2D material bare, PH and RH passivated.

In the paper has been investigated TiO_2 structure.

- Without the passivation, the bare (001) surface of TiO_2 shows

semiconducting character with a reasonably large band gap

(1.79 eV) owing to the stoichiometry of the surface Ti and

O dangling bonds and the large electronegativity difference

between Ti and O,which results in self-passivation (i.e.,charge

transfer from the Ti dangling bond to the O dangling bond).

- the PH passivation lowers the VBM energy and

raises the CBM energy and thus results in a large band gap due to quantum confinement effects. When the QD is passivated by PH, the dangling-bond states

are completely removed from the band gap, and the system

has a band gap, which is 0.73 eV larger than the bulk band gap

due to the quantum confinement effect.

You can also look at a simple but clear figure (4) which depicts the most relevant difference in the physical behaviour between PH and RH passivation.

Hope this might be helpful.

Best,

A.

http://icsnn2010.semi.ac.cn/bitstream/172111/23574/1/2012302.pdf

 @Angleo 

Thank you for you response. I have read this paper and what i understand from this paper is psuedo-hydrogen always show increase in band-gap but real hydrogen can give different trend based on nature (ionic/covalent) of you material (a comparison between real and psuedo hydrogen passivation ).

And i am looking for a way to make sure that psuedo-pssivation is done properly.

@Muhammad

I'm attaching in the following a figure about a work on 2D pristine and passivated silicene which shows the difference in DOS between the two condition of the system (look at the second column of pictures. I guess even in your case H atoms are localized on top of the system's atoms, so that p_z orbitals are more affected than p_x and p_y ones). The main effect is to increase a gap between valence and conduction bands, showing a Dirac delta-like peak at the Fermi level.

If you wish we can try to take a look to your plots and try to show some details that confirms passivation has been reached.

Best,

A.

Please, could you explain to me why you need to use a pseudo-hydrogen? Is it to complete dangling bonds at the end of slab, for example? This passivation only serves to stop the slab, eliminating spurious results edge? In this case, for me, if the system is done properly depends of how many electrons there are free in surface. Like a indium, 3 electrons in valence edge, in zinc blend structure, it is 0.75 electrons per bond. So, it is necessary a pseudo-hydrogen that have 0.75 electrons to saturate one dangling bond of Indium. Just it. Thus, the system is done properly. In this example, of course.